Smoke oven



June 27, 1944. AR. H, TR|NK| E l` 2,352,590

SMOKE OVEN Filed April 5, 1940 3 Sheets-Sheet l Alm] mi' fllHf. UUUH UUUUUUUU INVENTOR 4 7 7 E S 7' BY #75 i ATTORNEYv June Z 7, 1944.

R. H. TRINKLE SMOKE OVEN Filed April 5, 1940 3 Sheets-Sheet 2 C] MI y LUIIIHIL ATTORNEY A Trgsr June 27,'1944. R. H. TRINKLE SMOKE OVEN Filed April 5, 1940 s sheets-sheetv :s

INVENTOR Arzffsr- I ATTORNEY Patented June 27, 1944 o'FFl-CE sMoxr: ovEN v Robert n. Trinkle, chicago, ni., issignor to In- L# dustrial Patents Corpo corporation of Delaware ration, Chicago, Ill., a

AvvliwlnAn-il. 1940, sexismo. 32am 5 l' Y l Y I The present invention relates to a vfor and a method of treating food products.

An object of the present-I invention is to provide `a novel means for and method of conditioning comestibles such as meat products and the like. VAnother object of the invention is to provide -an apparatus in which and a method by which food products may be smoked, cured, dried vand cooked in a continuous process. y t

'Another objectof thisinvention-isto -provide a smoke house for the simultaneous and automatic smoking 'and cooking of food products;

Another' object of the invention isrto provide means for improved air 'circulation in a smoke Another object of the invention is to provide a treatment chamber for food products in which statc'pressure is automatically and .uniformly held'at a predetermined point. Y Another object of the present invention is to provide a novel apparatus operable on-the principle of a continuous circulating Vsystem embracing within its structure air passages including an enlarged chamber for the reception of comestibles to betreated. which incorporates means for ,introducing and controllingconditioning vapor used in the treating of the said food products.

Still a further object of the present 2invention is-to provide a novel device: for the treating of comestibles, such as meat products and the like, comprising` a continuousl air circulatingsystem embodying means providing air Viow passages including an enlargedtreating chamber'embody ing within its structure novel means for uniformly treating theproductswithin the said chamber inaccordance with predetermined desired operating conditions.' A

Still another object within thepurview of the present invention lis 'to provide a novel means for, and` method of, v subjecting comestibles, such as meat products and the like, in anenclosed of a uniformly flowing` tion to the food products in the said chamber 9 Claims.v (Cl. 9,9-229) novel deviceb circulating system to aerify a treatment chamber in which such product may be placed with a conditioning'atmosphere insuch a way as to provide for uninterrupted uniform flow of such conditioning atmosphere in enveloping relation ,to the said products without undesirable drafts in the said air in the vicinity of said products. whereby application of said conditioning' atmosphere to the products is uniform. i

. A further' object of the present invention is to provide a novel vmeans for,

of a continuously operable circulating system` for a conditioning atmosphere which is adapted to be projected into a treating chamber in the form sheet in enveloping relaand Vto provide for uninterrupted uniform ow of said conditioning atmosphere throughout the treatingregion of the said chambt in a uniform enveloping movement around such product, and tomaintain said conditioning atmosphere unifformly at predeterminedV operating` conditions.

compartment forming Dart of a continuous flow f circulating device, to a conditioning atmosphere adapted to encompass said products in a uniform enveloping movement whereby said conditioning atmosphere uniformly' .envelopes said products, and is uniformly applied to the surface thereof to produce uniformity in the processing of such products. y i j Another object embraced within thescope of the present'invention is to provide a `novel means for, and method of, treating food' products, such as meat or theA like, to produce uniformity `in the resulting processed product, the Ysaid invention involving the use of a continuously operating -in the system on treating chamber whereby release of pressure can MoreV particularly,- such means for, and method of, conditioning food'produ'cts such-as above mentioned contemplates the arrangement of the operating mechanisms controlling the distribution to and return flow of the conditioning atmsphere from the said treating chambery s o as to produce' the desired uniformflow thereof in the mannerind'icated, one illustrationof such ari rangement being" constituted bythe provision of means substantially at the same level in the said the introduction of the said conditioning vapor in the form of an elongated ilow stream into the environment of the products in the treating chamber and the withdrawal thereof fromv said region oftreatment, and creating a substantially Vuniform enveloping movement of the said conditioning air around such food product. l

A still further object of the present invention ls to provide a novel air pressure circulating system embodying theV characteristics set 'forth above, and in addition to which is incorporated,

novel means remote from the treating chamber for regulating, the pressure of the system and in such a manner as not to interfere in any way with the uniform vapplication of the conditioning vapor to the products lbeing treated in theirnormal. enveloping and circulatory movement in the system;V More particularly, such results are ac-Vv complished by providing pressure release means the return side of the said tandmethod of, rconditioning food products and involves the use assalito used in their treatment. IIhisA problemhas been further complicated by the fact that even though the advantages of air conditioning procedures in their applicability to the conditioning of meat products vhave been generally recognized, nevertheless such structures as have evolved are seriously decient in that instead of embracing one of the most essential requirements for the producltion, of uniformly conditioned products, namely,

-ment of the products disposed therein, one iilustrative example of such means as. herein disclosed being adapted to project into the environment of the products in said chamber a rapidly and uniformly moving ilow stream in Athe form of a sheet.

Still another object comprehended by the pres- -ent invention is to provide -in an air pressure circulating system for treating food products various means for introducing conditioning gases incontrollable amounts to replenish and revivify the circulating 'conditioning atmosphereVV of the system and to control static pressure of the-system in accordance with the introduction'iof said conditioning atmsphere. Y K i Still a furtherobject of the present invention is to provide in an air pressure circulating system fof the type herein contemplated novel control means operable automatically in accordance with lpredetermined settings for controlling. such con-' ditioning factorsas thepressure, temperature and humidity of the circulating atmosphere.y As a still further object of the present' invention,.novel means is contemplated for theI various A control'mechanisms whereby .the condition andv character of the circulating atmosphere `of the system can be controlled as desired and inY accordance with the processing contemplated for Vthe'particular products being treated.y Numerous devices have been proposed fromA time to time for curing and smoking meat products. It `has been proposed to simultaneously cookand smoke such a product, or otherwise combine in one structure means for carrying on two or more stepsin the treatment of meat products. Such devices, however,rhave not operated satisfactorily as prior designers and operators did not, fully understand the numerous factors upon 'which successful operation depends. The present uniform application of the conditioning gases to thev product being treated, the same have merely Yrelied upon the conventional uncontrolled introduction of such conditioning air into the system for the particular productsV undergoing treatment and the somewhat promiscuous application of suchair to the products being treated. 'l'.his results in the failure to produce uniformity in successive batches of the particular products undergoing treatment. Uniform characteristics of the process products is desired by all meat processors, and the like, to provide Vuniform standard lcharacteristics for the particular processed prod- .ing particularly to theprocessing of meats, the

heating of th'e said products for initial curing those involved in the processing 1or conditioning` Y of food products, and particularlymeat and the like, that air conditioning principles could be used and are highly desirable iny the-processing -of such products, nevertheless such devices as have been constructed 'heretofore to bperate in accordance with such principles have had ameasuresof success onlyA in the fleld,;due principally to the failure to embody certain desirable and essential characteristics and features of such devices.

Itis necessary, also, in constructing such a device to permit adjustment of the conditioning air as desired. Merely illustrative ofthe need for flexibility in the operation of such device,

among which is'their quality, texture, ,color and moisture content, all of which factors are determinative of a particular regulated process to be purposes, the subsequent introduction of moisture and smoke-laden air with a proper smoke ratio in theV system, and the introduction of Aheated air for cookingof the particular products undergoing processing, any one or all of which may be carried out either alone or in combination, and either simultaneously or progressively, in accordance with the processing requirements. Such devices must of necessity, in order to operate in an eilec- Vtive and eillcierit manner, embody flexibility in their operating characteristics which, although recognized as a desirable desideratum in the il'eld of operation, nevertheless has not been embodied in the developments of the prior art.

The present invention has, therefore, proceeded upon thetheo'ry of embracing within its scope the novel features andattributes'of'air conditioning devices and methods of operation, supplemented by particular considerationfor the adapt-- ability of such constructions andv methods tothe particularfproblems involved Ain the conditioning of comestibles, andparticularly the. processing ofmeat products, which require adequate and close control of temperature, humidityr smoke ratio and static'rpressureand the application of these conditioning agents totheY said meat products, and the like, undergoing treatment. I have discovered that successful operation ofl such air conditioning devices require especially close and accurate control of static pressure within the device. Other objects, features, capabilities `and advantagesare comprehended bythe invention, as will laterl appear andas are inherently possessed thereby. 'y

VReferringto the drawings:

-Figure lv is a. plan view, partly in section, of a.

device for treating foodproducts in accordance with the present invention:

Figure 2 is a view in section taken inthe plane` line 27-'1 of Figure 1 of the draw- Figure 4 is aV rear end view ofthe device shown. in Figures l to 3, inclusive, of the drawings;

1 f Figure 5 isa diagrammatic sketch of control mechanism for use Vin conjunction with the device according Ato Figures 1 to #inclusiva oiV the drawings.

An embodiment selected to illustrate the present-invention is disclosed in detail Vin the drawings. Briefly, it comprises an air circulating system embodying in its construction an Venlarged chambenor smoke oven I, and air flow passages formed in part by circulating ductsfgenverally referred to as 2, communicating therewith, as will be later hereinafter more fully disclosed. The device in accordance with the drawings is Yshown asmounted upon a suitable floor 3 asa "support, the said chamber I having itsfloor surfacev 4 'sloped asindicated inv the drawings to "merge with a drain for the disposal of waste ulds, and particularly wash waterused'in cleans- I1 maybe provided-with means for varying the discharge of said air into the intake duct-II.

` Maniromrzl. is provided with afresh air lmet the mixing dampers are completely open, and

4 when the fresh air intake dampers are completely open the mixing dampers are partially closed,

i'or example, at an angle of 35 or 40 degrees. I

have found that the mixing dampers'so linked ing the sa-ld iloor 4 and the walls'of the chamber I.' The chamber I is of box-like construction having opposed side walls 6 'andi and front and rear walls 8 and 8 and a topwall or roof I0. -The said walls may be of kany suitable insulating material, such as"Cellotex or Insolite, covered with 'galvanized iron, and'may be of unit hinged d0ors II and I2, whereby admittance into the chamber I is secured for the introduction of food products which may be transported by means of trucks or.Y cages into the chamber I for treatment in accordance withv the present invention.

The circulating system, according. to the present embodiment, is formed in part by the flow ducts 2 comprising a supply or distributing Yduct I3 and the return ow maintaining ducts I4 and II. Each of the said ductsextendsinto treating chamber I :th-rough the` rear wall 9, and is located within the chamber'adjacent to the roofH The said supply` duct I3 is substantially Il. centrally disposed in respect of said treating chamber I, andcommunicates by way of a duct Ilfwith the discharge end of a -fan casing I1 of afanIO. The said return tlow maintaining ducts I4 and I5 are disposed on each side of the said supply duct I3 approximately midwaybetween such duct and the side walls 6 and 1, respectively, and both communicate by way of ducts I9A and 28, respectively, with a manifold 2I. l`-'llhe manifold 2|, in turn, communicates with the return duct 22 connected to the intake side of the fan housin; n. 'a housing n for cheater 24y upon the base orpedestal 25 is located between said manifold 2I andretu-rn duct 22. Thefhe'aterV 24 comrises steam coils -ora radiator (connected to'a steamline 23 provided with a valve 21 forregulating the amount of steam admitted 'to the said heater 24. 'Access to the interior of housing 23 for adjusting the coils or the radiator, or to remove any collection of dust, dirt or other'foreign material from the housing or heater, is obtained through closure members or doors 23 and 23. Adjacent pedestal 25vis another pedestal or base 3l adapted to support the fan housing I1 and ja motor 3l having pulley 32 which, through the medium of a belt 33, drives kpulley 34` mounted on vthe end of the shaft 35 of the fan rotor. The shaft-35 is journaled in suitable bearings, not shown, in the fan housing I1. Inasmuch as the invention contemplates lthe possibility ofl varying the air flow within the circulatingsystem, the said' motor 3I or fan Il enclosed within housing to the freshk air intake dempers more thoroughly mixes the fresh air with that in thef'manifoldV and aids in the effective operation of the device.

A relatively large `steam,V nozzle-39 is`V located ingreturn duct 22, preferably intermediate the heater 24` and the air intake side of fan I8. This nozzle -is also connectedwith the steam 1ine28, which connection is likewise equipped with a valve 40 for regulating the amount of steam'admitted thereto.

Duct 4I connects manifold 2| with an exhaust duct 42.

lwith suitable valvefmeans, such as damper 4,3.

In most installations moreethan one smoke oven is required,-in which case the exhaust duct 42 may serve the entire .battery of ovens. The exhaust duct 42 connects with a fan 44, operatedby a motor 45, the exhaust air being delivered ture and ...a humidity regulating means 5I', and

the chamber I is equipped with a static pressure regulating means 52. Preferably each-of Vthese regulating means is adjustable from the outside of manifold A2| and chamber I; so that the'controls can be set by theoperator from the outside. .A diagrammatic view showing the layout of I prefer that these, regulating means operate by compressedair which maybefurnished-by an air compressor, not shown. The static regulator 52 is located withiny the treating chamber I, but should be set or .controlled from the'outsidev of the chamber I,r and should. be located in some suitable place where` the controls are easily accessible.VV .Anair line'53 connects the' sourcevof air pressure with the static pressure regulator line 54 connects the regula- 52, anda second air tor 52 with motor 55 which operates the damper 43 in the exhaustconnecting duct 4|, so that- Y treatingchamber I exceedsa predetermined flgure,rthe

when the static pressre; within the damper 43 is automatically opened. I prefer that exhaust fan V44 operate continuously so that when the damper 43 is opened, atmosphere is withdrawn from the chamber I,` therein reduced. ASo long as thefstatlc pressure 'withingthe said chamber I does not exceed the y predetermined figure the damper 43 in the exvhaustconnecting duct 4I is closed. i AIn practice the static pressure regulator 52 does not need to The connecting duct 4I is equipped V the regulating instruments is shown in Figure '5.

and the pressure.

`is always 'installed to operate reversely to closed.Y For example, when the willbe completely operate the fresh air damper 31 as the pressure increasing as longas the fan Il is operatln. Y 1 @Y suitable temperature and humidity regulator means II mayv comprise a dry bulb ll, a wet bulb l1, both located Vwithin the manifold 2l. The

. `dry bulb 56 and the wet bulb 51 connect by means 4 of gaseoustubes il and 59 respectively, with a double pen recording regulator 60 which may be flocated in any suitable place, such as adjacent toV the controls' of the static` regulator 52. ThisV regulator 60 also connects with the source of air pressure by means of air line 6I. The dry bulb Il regulates thetemperature of thesair within the air circulating system 2, while-the wet bulb Il regulates the humidity therein. Thewet bulb l1 operates a valve, not shown, within Vthe regu- `lator 6B which controls the air pressure in air Y Vvalve I0, the fresh air damper 31 will be closed. Y When the humidity falls below a predetermined ngure,- the valve Il is opened and steam is admitted to steam nozzle 39 and' thus int'o'the return duct 22 until the desired humidity in the `treating chamber I is reached. When the humidityr within the treating chamber I'reaches the supply duct Il, v which is adjacent to the ceiling Il thereof. 'It is provided with a series of nozzles 01. two rows being disclosed. v'l'.he row of nozzles' Il on `the aide of adjacent to return duct Il. is adapted to distribute the circulating fair in the form ofda sheetinto the environmentv ofthe foodproducts disposed within chamber I and substantially beneath the returnduct I4, and the other row of nozzles 6l is likewise adapted to operate inV a similar manner for projecting theair in the form'of a sheet into ythe environmentV of other food products to beV treated diswithin the treating'chamber` land substantially beneath theretupn now maintaining duct I5. Y This arrangement of the nozzles, however, may befmodliled as desired, to effect the results in accordance with theinvention, and the l arrangement as herein depicted is merely one ilthe desired point, the valve is closed, and no- Y further moisture is admitted to* the treating chamber, or to the circulating ducts 2 until the humidity again falls below the desired point. If, on the other. hand, the humidity is excessive, the fresh air dampers I1 are automatically opened. permittingfresh air to enter and bringing `the humidity down'totln desired point, Y

The dryV bulb S6 operatesa'valve withinrthe regulator 60 which controls the air pressure in air line 08 connecting theregulator 6l with aV motor II, which, in turn, `operates the valve Il on the steam line `2l supplying steam to the heater I4. When thejt'emperature within the manifold 2| is lower than a predetermined ilgure, steam is admitted tothe heater 2l, heating the air as it. ilows through the circulating system. When the temperature gets ,tothe n valve 21 shuts` olf the supply Iofsteam to the heater 24.V In practice,`- no special means for. 1 cooling thegair is necessary are undesirable, and heat. By using anticipating type controls close TAand accurate regulation issecur'eil.

During operation of the air circulating system above described, the rotorof fan Il forces the conditioning atmosphere into duct V Ifto'be discharged into the chamber I through the distributing duct I 3, after through the return flow maintainingducts Il and I I,the manifold 2l, the'rturnduct 22, and into the intake side of the fan Il, and is again recir-v culated in the manner indicated, Y

'I'he present invention is with the proper distribution of the flow of conditloning air 'in thechamber I f As-a part of said distributing Vsystem the said supply duct YI3 ein tendssubstantiallythroughoutithe length of the treatingchamber I, and is.,.approximately'cen trally disposed in ,saidY chamber `and islocated predetermined pointv the` as abrupt changes' the system will always lose a very.

which the fsame is returned particularly concerned mentl of the air within sheet in the circulation of air'takes place within the (of the return ducts such as Il,

vlengththereoiV to provide for this uniform flow.

The said return flow maintaining ducts I4 and II are each located laterally of the supply duct I3` and are substantially of t same length as said'duct I3.f These return ucts are disposed at substantially the same level as vduct I3, and are approximately midway between such-supply duct VVI3 and the sidewalls 6 snail, respectively.

' Each of said return ducts is provided with a plurality of openings -68 on the side opposed to the Supply duct I3, and similar openings, such as Il, on the. bottom thereof and between the `said openings V68. The openings maybe controlled by slide' dampers, not shown, or the like,for reg. ulating'the flow capacity of the said ducts. Furthermore. eachY of the return ducts may be provided adjacent rear wall -I with a `valve means. or damper, such as 10, whereby each duct may be completely closed to prevent passage of air therethrough," which dampermay be controlled by a quadrant 1I, or .other suitable means, manually manipulablefrom the exterior of the duct.

In accordance with the present invention. the

return ducts I4 and. II- are so located in respect olf-the supply duct I3 that the circulating moveto produce uniformity in the circulation `of con; ditioning atmospherefaround each of the food products. which may be. placed in the treating chamber I. Illustrativeof themanner in which treating chamber I, reference may be malle to one only inasmuch as the circulation of air within the system on each side of the supply duct takes place ner. Accordingl to the operation of the circulating system illustrated. the flow of air into the supply` ductv Aunder the :pressure maintained by operation of the fan results inthe rapid ejection of the said aix-through the nozzles tito produce.V a flow` sheet projecting down-into the environ-V products being'V treated in the p ment'of the food chamber If.

The normal movement of this now products is laterally in an enveloping movement theA chamber lv takes placeV in a similar man'- immediate environment ofthe said I on theregiilators I and Il.l

of substantial depth to encompass the said food products, and to cause norme] circulatory movement of `thelsaid air` laterally and upwardly toward'the return duct I4. 'Ihe circulating air in the system is returned to the-intake side of the fan I8 through the openings Il and sfof the return flow maintaining duct I4. This is a continuous operation under normal operating conditions, and this ,circulatoryjenveloping movement of the projected air takes place under uniform now, free from vortical or other disturb'- ances so that the food products are uniformly treated with the said .conditioning air enveloping thesame, as will-be later more-fully disclosed.

In order to'regulate the pressure within the treating chamber -.I without disturbing the normal uniform flow of the conditioning air therein,

provision-finas been made to relieve such pressure by the pressure release means heretofore zdescribed, including the exhaust duct 42 connecting with the manifold 2|. Thus, by proper operation l i of the'damper 43, the exhaustedv atmosphere is removed from the system remote from thetreating chamber I. Pressure within the 'device can, therefore, be regulated without causing vortical movement or Awhirlswithin thev conditioning air of the treating chamber I.

In operation, the device .illustrative of the present invention is loaded lwith product to be processed, such as sausage, which is brought in loaded on racks or sausage sticks, carried by cages or trucks. These are-.placed so that the center' of the `cage or truck is approximately underneath the return ducts I4 or I5. The doors II and I2 are then tightly closed and the controls for the temperature, humidity and pressure regulating means are set by the operator. Ordinarily, products such as sausage will be kept in a dry smoke at an elevated temperature for a piod, after which the temperature is raised, and the relative humidity increased, and these conditions maintained for another period while the product is completely processed. Temperature, relative humidity and static pressure within the oven are controlledf' automatically ate-.any desiredlevel atv any ,timelggthe operator changing the controls Conditioning atmosphere,l comprising' nr lthe main smoke-laden air,`is circulated in the system f as described above to uniformly envelop the products in the treating chamber I. Under normal operating conditions, such uniformity of application ofthe, said conditioning air to the products is accomplished by maintaining a high velocity of discharge for the same at .the discharge nozzles, usually approximately two thousand feety per minute, or-lesser, or greater, as conditions 'warrant.

treating chamber I through the openings BB and II in return ducts I4 and. I5, and then passes generated in the smoke generator 41 and is pulledout through the'duct 4l by the fan Il, and is '50 receiving chamber and in part by Supply and re- Said smoke laden air is withdrawn from the Control of the introduction of` smoke into the system is affected by the vdamper 4S,l which may be manually-manipulated to secure the proper smoke ratio in the circulating' atmosphere of the system. i

The Idesired relative humidity inside the chamber I is maintained vby the admission of steam `through steam nozzle 39 and fresh air through inlet 36. If the humidity in the chamber I is raisedabove the desired point, the fresh air inlet damper 31 automatically opens, permitting fresh air to enter and bringing the humidityr down to the desired point.l If, on theother hand, the humidity ldrops, below ythe [desired point, the steam valve 40 automatically- .opens and admits vlive steam through the" steam inlet `39 which builds up the humidity to the desired point. By the intermittent operation of the fresh air damper and the live steam valve the relative humidity inside the treating chamber I caribe maintained at any desired point.

As 'fresh air is pulled'in through inlet 36 and smoke through duct 41, a pressure is created inside the chamber 'I which, when the predeter mixed with the smoke-laden air being circulated in the",ristrettiA to revivify and reactivate the same.

mined pointis reachedfis relieved through exhaust damper 43. y

As abovedescribed, location roi? the pressure exhaust means in remote relation to the treating kchamber makes for more uniform treating conditions in the said chamber, inasmuch as the movement and circulation of the conditioning atmosphere of the system is unaifectedby release of such atmosphere thereof from the treating chamber. Release would-otherwise cause vortical and other objectionable eddiesy and cross currents to be set up in the vicinity of the vprodnots, thus leading to lack of' uniformity in the treatment of saidy products.

WhiienI. have` herein described, and in the drawingsshowm an illustrative embodiment of the invention, it is to be understood vthatI the invention is not limited thereto, but may comprehend other constructions, arrangements-of parts,

details, features and method steps without departing from the spirit oi' the invention.

i 1. In a device for treating comestibles, the combination of. an air pressure circulatingl system formed in part by an enlarged comestible turn iiow maintaining means communicating with said enlarged comestible receiving chamber, said supply means having means for discharging air into said chamber in enveloping relation to comestibles disposed in said chamber, said return ilow means being disposed in relation to said supvply means for maintaining said enveloping circulatory movement of said iluid body in said chamber, means for introducing air into said system toxsupplemnt the air circulating therein,

mea'ri's for regulating-the pressure of said air in said system, means'for supplying a vapor into said system, means for heating the circulating air in said system, and automatically operable means for controlling the said pressure regulati ing meanaair and vapor supply means, and said heating means to condition the said air within the system in accordance with predetermined operating requirements.

2., A device for treating comestibles, comprising an insulated chamber, means for continuous f circulation of heated, smoke-laden air in saidv chamber, and its removal therefrom, said means including air conditioning means comprising a smoke generator, a fresh aid inlet, means for heating said air and smoke, a steam nozzle. and a fan, andducts cmnectiugV saidair conditioning from said' chamberrfor: automatically maintaining a desired static pressure therein in response to the diil'erential pressure between the, inside 1 and outside of said chamben y 3. A smoke oven comprising anv insulated chamber, means for introducing into, and' circulating within', said Ichamberconditioned comes- 'tible treating air and removal therefrom, and for reintroducing the same intolsaid chamber, said means comprising a supply duct centrally-disposed in said chamber, ladjacent to the ceiling thereof and extending substantially the length of the oven, which supplyductis equipped with a plurality of downwardly pointing nozzles. return ducts provided with a plurality of openings and and humidifying the air circulatingl within said chamber and ducts, means foi-supplying said conditioned comestible treating air into said chamber, means forthe introduction .of smoke into said conditioned comestible treating air, and means. remote from said chamber for maintaining a desired static pressure' therein, comprising an exhaust duct connected to said return ducts remote from said chamber, and containing dampoers automatically operated by a pressure vregu lating devicel operating in response to the diifer- 'ential pressure betweenthe inside and outside of said chamber.

4. In a smoke ovenl adapted to process comesytlbles, means for automatically circulatingtherein conditioned comestible treating air ata predetermined temperature, lhumidity and static pressure, comprising a variable speed blower fan, a supply duct leading from said blower fan into said oven, said supply duct being centrally disposedv within said oven adjacent to the ceiling `thereof, and extending substantially the Vlength of said oven, which supply4 duct withinsaid oven is vequippedl with a Aplurality of V downwardly opening nozzles, returnl ducts` within saidoven located laterally of and at substantially the same level as the said supply duct, a plurality of closable openings in saidret'urnfducts within said oven, a manifold connecting said return ducts to saidl blower fan, an exhaust duct leading from said manifold to the outer atmosphere, a damper means for closing vsaid exhaust duct, a pressure `regulator within the said ov,en automatically op- -ing said damper means in the fresh air' intake and the valve in said moisture injection means, a means for heating the-atmosphere in said manifold, means for regulating the temperature of the atmosphere. in saidV manifold automatically operating-said heating means, and means for injecting smoke into said manifold.

5. An apparatus vi'or treating food products comprising a gaseous pressure circulating system means with said chamber. and i, means remote assasoo including an enlargedtreating chamber and sup- '.ply and vreturn tlg'w maintaining means communicating with s id chamber. charging means I. for adding i'resh gaseous fluid to said system and discharge means for releasing used gaseous fluid from said system,` and means for maintaining the static pressure in said chamberat a predetermined point by automatically regulating the release ofv gaseousfluid thro said discharge means in response to the di erential pressure l between the inside and-outside of said chamber.

6. An apparatus for treating food products y comprising a gaseous pressure circulating system formed in part by an enlarged treatingchamber and in part by supply and return flow maintain-7 ing means communicating with said chamber,

, means for adding .fresh gaseous charge toV said 4located laterally of, and at substantially the same level as, the said supply duct, means for heating system, means for withdrawing used gaseous fluid kfrom `said system,V means for adding moisture to said system, and means for controlling the humidity at a predetermined value in said treating chamber byautomatically regulating the addition of said freshgaseous charge and said mois- -ture in response yto the relative humidity in said chamber.

7. A method of treating food products which comprises circulating ay gaseous treating medium in enveloping relation to the food products in an enlarged treating zone, charging fresh treating medium to said zone, -discharging used treating medium fromsaid zone'and maintaining the static pressure in said zone at a predetermined point by automatically vregulating the discharge of said used treating medium in response' to the differential pressure between fthe outside of said zone. .f A.

8. A method of treating food products which comprises circulating a gaseous treating medium in a closed circuit including an enlarged treating inside land 40 zone. causing the treating medium to envelope uniformly the food products in the enlarged zone, charging fresh treating Amedium to said l circuit, discharging used medium fromsaid circuit, adding moisture to said circuit and controlling the humidity at a predetermined value in said treating zone v-by automatically regulating the charging ofv said yfresh treating medium andsaid `moisture in response tothe variations in relative'v humidity in said chamber.

`il. A method of treating food products under controlled conditions ofhumidity and pressure which, comprises circulating a gaseous treating -medium in enveloping relation to the food products in an enlarged treating zone, charging fresh in humidity therein.

treating lmedium to said zone, discharging used treating medium lfrom said zone, adding moisture to said zone, maintaining the pressure in said zone at a predetermined point by regulating the discharge of said used treating medium automaticallyin response to the differential pressure between the inside and outside of said zone and maintaining the humidity at` a predetermined point in said zone by regulatingv the addition of moisture automatically in `response to variations 

